Good spot regarding the non-Free licence. Instant deal-breaker. It forbids distribution of the source-code, forbids reverse-engineering, and forbids commercial use.
Also the license does not forbid commercial use, the free license allows use in commercial software by companies up to $100K in gross revenue. For use in commercial projects beyond that, we have pricing available on our website [3].
* [1] https://github.com/ultralight-ux/WebCore
* [2] https://github.com/ultralight-ux/AppCore
* [3] https://ultralig.ht